O461.21 99031424SiH<sub>4</sub>辉光放电的质谱研究=Investigation of SiH<sub>4</sub> inglow discharge by the mass spectrum[刊,中]/姚若河,林揆训,石旺舟,林璇英（汕头大学物理系.广东,汕头（515063）...O461.21 99031424SiH<sub>4</sub>辉光放电的质谱研究=Investigation of SiH<sub>4</sub> inglow discharge by the mass spectrum[刊,中]/姚若河,林揆训,石旺舟,林璇英（汕头大学物理系.广东,汕头（515063））//功能材料.—1998,29（2）.-178-179报道了采用四极质谱计在制备a-Si:H薄膜的PCVD系统中对SiH<sub>4</sub>射频辉光放电进行在线的质谱研究。获取了在不同电离电压下的SiH<sub>4</sub>展开更多
This work is concentrated on elucidating the mechanism of the electric field enhanced water dissociation. A simple model was established for the theoretical current-voltage characteristics in water dissociation proces...This work is concentrated on elucidating the mechanism of the electric field enhanced water dissociation. A simple model was established for the theoretical current-voltage characteristics in water dissociation process on a bipolar membrane based on the existence of a depletion layer and Onsager's theory. Particular attention was given to the influence of applied voltage on depletion thickness and the dissociation constant. The factors on the water splitting process, such as water diffusivity, water content, ion exchange capacity, temperature, relative permittivity, etc. Were adequately analysed based on the derived model equations and several suggestions were proposed for decreasing the applied voltage in practical operation. The water dissociation tests were conducted and compared with both the theoretical calculation and the measured current-voltage curves reported in the literature, which showed a very good prediction to practical current-voltage behavior of a bipolar membrane at high current densities when the splitting of water actually commenced.展开更多
Based on orthogonal experiments,the effects of voltage,frequency,duty ratio and their interactions on the thickness and corrosion resistance of coatings prepared by plasma electrolytic oxidation(PEO)on aluminum in an ...Based on orthogonal experiments,the effects of voltage,frequency,duty ratio and their interactions on the thickness and corrosion resistance of coatings prepared by plasma electrolytic oxidation(PEO)on aluminum in an alkaline silicate-containing electrolyte were investigated.The thicknesses of these coatings were obtained by measuring their cross-section using Image J software.Their corrosion resistances were evaluated in HCl and NaCl media through spot test and electrochemical test.The results show that the experimental design of this study is the key to investigate the interactions among these electrical parameters.Additionally,not only each independent factor,but also their interactions exhibit a remarkable influence on the coatings.The combination of high voltage,low frequency and large duty ratio significantly increases the coating thickness and content of the corrosion resistance phase,and thus improves the corrosion resistance of the coating in HNO3 medium.Conversely,the coating possessing the densest microstructure and best corrosion resistance in NaCl medium is obtained when low voltage and high frequency match with a small duty ratio.展开更多
The new techniques were presented for preventing undesirable distance relay maloperation during voltage collapse and power swings in transmission grids. Initially, the work focused on the development of a fast detecti...The new techniques were presented for preventing undesirable distance relay maloperation during voltage collapse and power swings in transmission grids. Initially, the work focused on the development of a fast detection of voltage collapse and a three-phase fault at transmission lines by using under impedance fault detector (UIFD) and support vector machine (SVM). Likewise, an intelligent approach was developed to discriminate a fault, stable swing and unstable swing, for correct distance relay operation by using the S-transform and the probabilistic neural network (PNN). To illustrate the effectiveness of the proposed techniques, simulations were carried out on the IEEE 39-bus test system using the PSS/E and MATLAB software.展开更多
The control of the stability of the filament tension is one of the crucial techniques ensuring the component quality of the composite materials. The open-loop tension control system, with industrial control computer a...The control of the stability of the filament tension is one of the crucial techniques ensuring the component quality of the composite materials. The open-loop tension control system, with industrial control computer as the core, magnetic particle clutch as the actuator, equipped with compensation technique is researched and manufactured. It can assure the tension control stability of the yarn in filament winding process and increase the control precision of the whole system.展开更多
Applying negative bias voltages caused significant microstructure changes in arc ion plated CrN films. Nanocrystalline microstructures were obtained by adjusting the negative bias voltage. Structural characterizations...Applying negative bias voltages caused significant microstructure changes in arc ion plated CrN films. Nanocrystalline microstructures were obtained by adjusting the negative bias voltage. Structural characterizations of the films were carried out using X-ray diffractometry (XRD) and high-resolution transmission electron microscopy (HR-TEM). The results indicated that increasing ion bombardment by applying negative bias voltages resulted in the formation of defects in the CrN films, inducing microstructure evolution from micro-columnar to nanocrystalline. The microhardness and residual stresses of the films were also affected. Based on the experimental results, the evolution mechanisms of the film microstructure and properties were discussed by considering ion bombardment effects.展开更多
This study presented an off-line identification method of induction motor (IM) parameters. Before startup,the inverter drive performed automatically a modified DC test, a locked-rotor test, a no-load test and a step-v...This study presented an off-line identification method of induction motor (IM) parameters. Before startup,the inverter drive performed automatically a modified DC test, a locked-rotor test, a no-load test and a step-voltage test to identify all the parameters of an induction motor. No manual operation and speed signals were required in the process. In order to obtain effective messages and improve the accuracy of identification, the discrete fast Fourier transform (DFFT) and the least-squares were used to process the signals of currents and voltages. A phase-voltage measuring method for motors was also proposed, which measured directly the actual conducting time of three upper switches in the inverter without need for a dead-time compensator. The validity, reliability and accuracy of the presented methods have been verified by the experiments on a VSI-fed IM drive system.展开更多
Effects of various sintering methods such as spark plasma sintering(SPS), hot pressing(HP) and electric resistance sintering(ERS) on the microstructure and mechanical properties of commercial pure titanium(CP-Ti) powd...Effects of various sintering methods such as spark plasma sintering(SPS), hot pressing(HP) and electric resistance sintering(ERS) on the microstructure and mechanical properties of commercial pure titanium(CP-Ti) powder consolidations with particle size of <147 μm, <74 μm and <43 μm were studied. The smaller particle powders are densified to proceed at a higher rate. Dense titanium with relative density up to 99% is found to take place at 850 °C under 30 MPa of SPS and HP condition. However, in case of ERS, CP-Ti powders were densified almost at 950 °C under 30 MPa. The microstructure of sintered titanium is composed of equiaxed grains at 850-950 °C. The yield strength of sintered body composed of <43 μm powder is 858 MPa by using SPS at 850 °C under 30 MPa. When there is a higher content of small particle, the higher yield strength value is obtained both by using SPS and HP. However, when ERS is introduced, the highest yield strength is 441 MPa at 950 °C under 30 MPa, which shows much lower values than those by SPS and HP methods. ERS method takes much less sintering time compared with SPS and HP. Nevertheless, higher sintering temperature results in lower strength and elongation because of brittle fracture.展开更多
The emission of CuInSe2-based spark discharge plasma at atmospheric pressure in air has been investigated by optical emission spectroscopy method. The plasma was formed by action of the high voltage pulse generator （...The emission of CuInSe2-based spark discharge plasma at atmospheric pressure in air has been investigated by optical emission spectroscopy method. The plasma was formed by action of the high voltage pulse generator （with nanosecond pulse） on the corresponding electrodes （CulnSe2 compound）. The emission characteristics have been obtained for the spark discharge plasma at 3 mm interelectrode distance. It was established that the spark discharge plasma radiation was determined by decay products of the compound from which electrodes were made. The most suitable spectral lines for plasma diagnostics is atomic copper lines in the visible spectrum and atomic indium lines in UV （ultraviolet） and visible spectrum.展开更多
A three-dimensional mathematical model for the transferred-type argon arc was developed to describe arc force on the anode surface. The software ANSYS was employed to solve the model. The model includes a part of torc...A three-dimensional mathematical model for the transferred-type argon arc was developed to describe arc force on the anode surface. The software ANSYS was employed to solve the model. The model includes a part of torch and tungsten electrode to achieve more reasonable resuits. The arc temperature and flow fields were derived. And the influences of welding parameters on arc force were also studied. The simulated results show that arc pressure at the anode are dependent on the welding current, plasma gas flow rate and electrode neck-in, while not sensitive to arc length.展开更多
Experimental research of anode current and anode voltage influence on the speed of decaying plasma resistance change and the time ofthyratron cutoff. Anode current resistance increase is shown to cause thyratron cutof...Experimental research of anode current and anode voltage influence on the speed of decaying plasma resistance change and the time ofthyratron cutoff. Anode current resistance increase is shown to cause thyratron cutoff time increase in case of fixed anode voltage. In turn anode voltage increase in case of fixed anode current causes earlier increase of decaying plasma resistance growth speed and quicker apparatus cutoff：展开更多
High voltage pulse natural organic matter （NOM） toxic by-products. Fulvic acid discharge plasma can remove and produce no production of solution was treated by high voltage pulse discharge plasma in this paper. It w...High voltage pulse natural organic matter （NOM） toxic by-products. Fulvic acid discharge plasma can remove and produce no production of solution was treated by high voltage pulse discharge plasma in this paper. It was shown that： for the reason of thermolysis and oxidation, the pH and Oxidation Reduction Potential （ORP） of solution decreased gradually with the increase of peak voltage and fulvic acid solution concentration, meanwhile the temperature and turbidity of solution increased gradually. Adding hydrochlorid acid in the treatment could amplify the effect of plasma. When the concentration of NOM as the surrogate parameter, Ultraviolet Absorbancy Degree （UV254） increased slowly by the effect of plasma, while the degradation of Total Organic Carbon （TOC） was first-order reaction. The removal rate of TOC increased from 22.6% to 33.4% by high voltage pulse electrical field of 35 kv, and from 25.6% to 36.7% with the addition of hydrochlorid acid. This paper may provide some basis for the scale-up design of water treatment process by high voltage pulse discharge plasma with other technologies.展开更多
Blast pressure of C-H-O solvents on failed lithium-ion cells at the voltage range between 3.8 V and 4.18 V may be calculated by means of the simple semi-empirical equation, y = （Ia ＋ Jb）/（Ka ＋ Lb ＋ Me）, p is th...Blast pressure of C-H-O solvents on failed lithium-ion cells at the voltage range between 3.8 V and 4.18 V may be calculated by means of the simple semi-empirical equation, y = （Ia ＋ Jb）/（Ka ＋ Lb ＋ Me）, p is the initial density of solvent, Q is the chemical energy of explosion, v is the voltage. The values of a, b, c depend on C-H-O composition. Value of I, J, K, L, Mmay be estimated from the H20-CO2 arbitrary decomposition assumption. Blast pressure derived in this manner can provide preliminary protective estimation and it is compared with experiment results by adiabatic calorimeter.展开更多
文摘O461.21 99031424SiH<sub>4</sub>辉光放电的质谱研究=Investigation of SiH<sub>4</sub> inglow discharge by the mass spectrum[刊,中]/姚若河,林揆训,石旺舟,林璇英（汕头大学物理系.广东,汕头（515063））//功能材料.—1998,29（2）.-178-179报道了采用四极质谱计在制备a-Si:H薄膜的PCVD系统中对SiH<sub>4</sub>射频辉光放电进行在线的质谱研究。获取了在不同电离电压下的SiH<sub>4</sub>
基金Supported by the National Natural Science Foundation of China (No. 29976040), the Natural Science Foundation of Anhui Province (No. 99045431) and Youth Foundation of USTC.
文摘This work is concentrated on elucidating the mechanism of the electric field enhanced water dissociation. A simple model was established for the theoretical current-voltage characteristics in water dissociation process on a bipolar membrane based on the existence of a depletion layer and Onsager's theory. Particular attention was given to the influence of applied voltage on depletion thickness and the dissociation constant. The factors on the water splitting process, such as water diffusivity, water content, ion exchange capacity, temperature, relative permittivity, etc. Were adequately analysed based on the derived model equations and several suggestions were proposed for decreasing the applied voltage in practical operation. The water dissociation tests were conducted and compared with both the theoretical calculation and the measured current-voltage curves reported in the literature, which showed a very good prediction to practical current-voltage behavior of a bipolar membrane at high current densities when the splitting of water actually commenced.
基金Project(1111RJDA011)supported by the Creative Research Group Fund of Gansu Province,ChinaProject(SKLAB02015006)supported by the State Key Laboratory Open Fund of Advanced Processing and Recycling of Nonferrous Metals,China。
文摘Based on orthogonal experiments,the effects of voltage,frequency,duty ratio and their interactions on the thickness and corrosion resistance of coatings prepared by plasma electrolytic oxidation(PEO)on aluminum in an alkaline silicate-containing electrolyte were investigated.The thicknesses of these coatings were obtained by measuring their cross-section using Image J software.Their corrosion resistances were evaluated in HCl and NaCl media through spot test and electrochemical test.The results show that the experimental design of this study is the key to investigate the interactions among these electrical parameters.Additionally,not only each independent factor,but also their interactions exhibit a remarkable influence on the coatings.The combination of high voltage,low frequency and large duty ratio significantly increases the coating thickness and content of the corrosion resistance phase,and thus improves the corrosion resistance of the coating in HNO3 medium.Conversely,the coating possessing the densest microstructure and best corrosion resistance in NaCl medium is obtained when low voltage and high frequency match with a small duty ratio.
文摘The new techniques were presented for preventing undesirable distance relay maloperation during voltage collapse and power swings in transmission grids. Initially, the work focused on the development of a fast detection of voltage collapse and a three-phase fault at transmission lines by using under impedance fault detector (UIFD) and support vector machine (SVM). Likewise, an intelligent approach was developed to discriminate a fault, stable swing and unstable swing, for correct distance relay operation by using the S-transform and the probabilistic neural network (PNN). To illustrate the effectiveness of the proposed techniques, simulations were carried out on the IEEE 39-bus test system using the PSS/E and MATLAB software.
文摘The control of the stability of the filament tension is one of the crucial techniques ensuring the component quality of the composite materials. The open-loop tension control system, with industrial control computer as the core, magnetic particle clutch as the actuator, equipped with compensation technique is researched and manufactured. It can assure the tension control stability of the yarn in filament winding process and increase the control precision of the whole system.
基金Project(2010-0001-226) supported by the National Core Research Center (NCRC) Program through the National Research Foundation of Korea funded by the Ministry of Education, Science and TechnologyProject supported by the Fundamental R&D Program for Core Technology of Materials funded by the Ministry of Knowledge Economy, Korea
文摘Applying negative bias voltages caused significant microstructure changes in arc ion plated CrN films. Nanocrystalline microstructures were obtained by adjusting the negative bias voltage. Structural characterizations of the films were carried out using X-ray diffractometry (XRD) and high-resolution transmission electron microscopy (HR-TEM). The results indicated that increasing ion bombardment by applying negative bias voltages resulted in the formation of defects in the CrN films, inducing microstructure evolution from micro-columnar to nanocrystalline. The microhardness and residual stresses of the films were also affected. Based on the experimental results, the evolution mechanisms of the film microstructure and properties were discussed by considering ion bombardment effects.
文摘This study presented an off-line identification method of induction motor (IM) parameters. Before startup,the inverter drive performed automatically a modified DC test, a locked-rotor test, a no-load test and a step-voltage test to identify all the parameters of an induction motor. No manual operation and speed signals were required in the process. In order to obtain effective messages and improve the accuracy of identification, the discrete fast Fourier transform (DFFT) and the least-squares were used to process the signals of currents and voltages. A phase-voltage measuring method for motors was also proposed, which measured directly the actual conducting time of three upper switches in the inverter without need for a dead-time compensator. The validity, reliability and accuracy of the presented methods have been verified by the experiments on a VSI-fed IM drive system.
基金Project(K0004130) supported by the Fundamental R&D Program for Core Technology of Materials funded by the Ministry of Knowledge Economy,Korea
文摘Effects of various sintering methods such as spark plasma sintering(SPS), hot pressing(HP) and electric resistance sintering(ERS) on the microstructure and mechanical properties of commercial pure titanium(CP-Ti) powder consolidations with particle size of <147 μm, <74 μm and <43 μm were studied. The smaller particle powders are densified to proceed at a higher rate. Dense titanium with relative density up to 99% is found to take place at 850 °C under 30 MPa of SPS and HP condition. However, in case of ERS, CP-Ti powders were densified almost at 950 °C under 30 MPa. The microstructure of sintered titanium is composed of equiaxed grains at 850-950 °C. The yield strength of sintered body composed of <43 μm powder is 858 MPa by using SPS at 850 °C under 30 MPa. When there is a higher content of small particle, the higher yield strength value is obtained both by using SPS and HP. However, when ERS is introduced, the highest yield strength is 441 MPa at 950 °C under 30 MPa, which shows much lower values than those by SPS and HP methods. ERS method takes much less sintering time compared with SPS and HP. Nevertheless, higher sintering temperature results in lower strength and elongation because of brittle fracture.
文摘The emission of CuInSe2-based spark discharge plasma at atmospheric pressure in air has been investigated by optical emission spectroscopy method. The plasma was formed by action of the high voltage pulse generator （with nanosecond pulse） on the corresponding electrodes （CulnSe2 compound）. The emission characteristics have been obtained for the spark discharge plasma at 3 mm interelectrode distance. It was established that the spark discharge plasma radiation was determined by decay products of the compound from which electrodes were made. The most suitable spectral lines for plasma diagnostics is atomic copper lines in the visible spectrum and atomic indium lines in UV （ultraviolet） and visible spectrum.
基金National Natural Science Foundation of China(No.50275106)
文摘A three-dimensional mathematical model for the transferred-type argon arc was developed to describe arc force on the anode surface. The software ANSYS was employed to solve the model. The model includes a part of torch and tungsten electrode to achieve more reasonable resuits. The arc temperature and flow fields were derived. And the influences of welding parameters on arc force were also studied. The simulated results show that arc pressure at the anode are dependent on the welding current, plasma gas flow rate and electrode neck-in, while not sensitive to arc length.
文摘Experimental research of anode current and anode voltage influence on the speed of decaying plasma resistance change and the time ofthyratron cutoff. Anode current resistance increase is shown to cause thyratron cutoff time increase in case of fixed anode voltage. In turn anode voltage increase in case of fixed anode current causes earlier increase of decaying plasma resistance growth speed and quicker apparatus cutoff：
文摘High voltage pulse natural organic matter （NOM） toxic by-products. Fulvic acid discharge plasma can remove and produce no production of solution was treated by high voltage pulse discharge plasma in this paper. It was shown that： for the reason of thermolysis and oxidation, the pH and Oxidation Reduction Potential （ORP） of solution decreased gradually with the increase of peak voltage and fulvic acid solution concentration, meanwhile the temperature and turbidity of solution increased gradually. Adding hydrochlorid acid in the treatment could amplify the effect of plasma. When the concentration of NOM as the surrogate parameter, Ultraviolet Absorbancy Degree （UV254） increased slowly by the effect of plasma, while the degradation of Total Organic Carbon （TOC） was first-order reaction. The removal rate of TOC increased from 22.6% to 33.4% by high voltage pulse electrical field of 35 kv, and from 25.6% to 36.7% with the addition of hydrochlorid acid. This paper may provide some basis for the scale-up design of water treatment process by high voltage pulse discharge plasma with other technologies.
文摘Blast pressure of C-H-O solvents on failed lithium-ion cells at the voltage range between 3.8 V and 4.18 V may be calculated by means of the simple semi-empirical equation, y = （Ia ＋ Jb）/（Ka ＋ Lb ＋ Me）, p is the initial density of solvent, Q is the chemical energy of explosion, v is the voltage. The values of a, b, c depend on C-H-O composition. Value of I, J, K, L, Mmay be estimated from the H20-CO2 arbitrary decomposition assumption. Blast pressure derived in this manner can provide preliminary protective estimation and it is compared with experiment results by adiabatic calorimeter.
